Electrical condenser



Sept. 11, 1934. E (LUNG 1,973,342

ELECTRICAL CONDENSER Filed April 25, 1931 Qvwemtoz PRESTON E. GILL/N6 Patented Sept. 11, 1934 ELECTRICAL CONDENSER Preston E. Gilling, Haddon Heights, N. .11., as-

signor to Radio Eondenser Company, Camden,

Application April 25, 1931, Serial No. 532,814 4 Claims. (Cl. 175-415) This invention relates to an electrical condenser particularly useful in connection with radio receiving sets and more especially fora set designed to receive ultra-high frequency waves. However, one form of my invention herein described may be used to great advantage in a receiving set covering the present broadcast wave band from 500 to 1500 kilocycles, or 200 to 690 meters wave length.

A condenser to be used in receiving sets for frequencies higher than the present broadcast wave band as above set forth, requires but very little capacity, and this capacity, to get the best results, should be arranged so as to be readily adjustable, whereby variation in manufacture or variations in the capacity of the different circuit units may be readily compensated for, sothat the condensers may be arranged in gang and operated by a single control and at the same time secure proper sharpness of tuning in each tuned circuit for each setting of the control device.

In the design of condensers used for the presentday frequencies previously referred to, the edge efiects are usually neglected because they ordinarily comprise an extremely small percentage of the total capacity of the condensers and really efiect only the minimum or initial capacity of such condensers. In the design herein described, the condenser, except for one case which will be later referred to, depends entirely on the edge efiects; or, stated another way, the edge capacity comprises the capacity of the condenser.

My invention will be readily understood by those skilled in the art by reference to the annexed drawing, wherein:

Figure 1 shows a plan view of a three-gang condenser of my present design.

Figure 2'is a view on the line 22 of Figure 1.

Figure 3 is a part elevation of the left-hand portion of Figure 1.

Figure 4 is a. plan view of a four-gang condenser suitable for use in the present-day radio receiving set, in which is incorporated one form of a part of my invention.

Figure 5 is a plan view of one form of my in vention which may be used in connection with the condenser units shown in Figure 4.

Figure 6 is a side elevation of an element of the condenser plate shown in Figure 5, illustrating how the elements comprising the plate of Figure 5 may be modified when used in the arrangement shown in Figure 1.

Referring now to the details wherein like numbers refer to corresponding parts in the various views, 1 is a framework having end plates 2 and 3 which support a rotary shaft 4 to which may be attached a dial or other operating device. Preferably, the frame 1 is U-shaped having side members 5 and 6 to which are attached insulators 7 by means of screws or rivets 8. Carried 30 on the insulators '7, is a stationary arcuately formed member 9 having lugs 10 attached to the insulators 7 by screws or rivets 11, holes 12 being provided in the sides 5 and 6 large enough so that the head of the screw 11 will not touch the side 5 frame members. Preferably, the lugs 10 have slotted holes therein so that the screws 11 may be loosened and the stator plate 9 adjustedlto get the proper alignment and air gap with re-- spect to the rotor member 13 which is carried on W a sleeve 14 fastened to the shaft 4 in any satisfactory manner as by set screws 15.

As will be more clearly seen from Figure 2, the stator plate 9 is merely a narrow strip of metal having lugs 10 bent outwardly at the ends thereof. Likewise, the rotor 13 is a narrow strip of metal; that is, the entire central portion is removed. The stator 9 and the rotor 13 may be provided with kerfs l6 and 17 respectively whereby the segments of metal between the kerfs may 30 be bent sidewise to vary the capacity of the condenser at different arcuate settings. The number of these kerfs may be varied to suit conditions; for example, they may be as many as shown in Figure 5.

In Figure 5, I have shown a condenser plate made up of a plurality of strips 18, the longest one of which, slightly modified, is shown in Figure 6. As illustrated, there are one hundred of these strips corresponding to the divisions now used on the ordinary dial. It will be understood that there may be one of these strips for each degree if the dial is arranged in degrees instead of divisions. The strips as shown, are set into and fastened in any satisfactory manner in a support member 19 having an enlargement 20 with a hole 21 therein to receive the shaft 4. It is also to be understood that the shaft 4 may be located at the center of the plate or to one side, as illustrated in Figure 5.

When the rotor plate as shown in Figure 5 is used in the arrangement of Figure 1, I prefer to bend over the outer end of the strip or section as indicated at 22, whereby the ends 22 may be ad- 05 justed so as to get the desired edge capacity at each division or degree setting of the dial. In addition to bending the ends 22 as above noted, the entire strip or section 18 may be bent transversely of the plane of the plate to assist in getno ting the required capacity for a degree or division setting.

The plates shown in Figure 5 can be very ad- .vantageously used in the gang condenser used for present broadcast purposes, such an application being illustrated in Figure 4 which shows four unit condensers 23, 24, 25, 26, arranged in a frame having support and shield plates 28, similar to that shown in Figure 1, the outer plates 27 of the rotor being similar to the plate shown in Figure 5. When this plate isused in sucha condenser, it is at once seen that compensation may be obtained, as has already been pointed out, for each division or degree setting of the condenser. In other words, where .at the present time the stations are fixed by the Government at ten kilocycles apart, I can obtain an exact setting for each and every ten kilocycles, thereby giving, as far as I am aware, the maximum efliciency in compensation.

While I have shown in Figure 5, one form of rotor plate for carrying my invention into practice, it will be understood that the outer stator plates may be likewise arranged and the method of obtaining the degree or division compensation may take some other form than that shown.

Having thus described my invention, what I claim is:

1. In an electrical condenser, a stationary element and a movable element arranged to move in edgewise relationship to said stationary element, at least one of said elements having a plurality of kerfs dividing said element into a plurality of areas, a small portion of the extremity of said areas being bent over substantially at right angles to the plane of said element, said areas adapted to be adjusted laterally at a desired arcuate point to slightly change the capacity between the elements, said bent-over por tions also being adjustable to slightly change the capacity.

2. In an electrical condenser, a stationary element and a movable element arranged to move in edgewise relationship to said stationary element, at least one of said elements arranged with a plurality of kerfs dividing said element into a plurality of areas, said areas adapted to be adjusted laterally at desired arcuate points to slightly change the capacity between the elements.

3. In an electrical condenser, a stationary element and a movable element arranged to move in edgewise relationship to said stationary element, at least one of said elements having a plurality of adjustable areas preferably in number equal to the divisions on a'scale associated with the condenser.

4. In an electrical condenser, a stationary element and a movable element arranged to move in edgewise relationship to said stationary element, at least one of said elements having a plurality of adjustable areas preferably not less than 100.

PRESTON E. GILLING.

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